Fastening the blades of axial steam turbines



Jan, 2, 1923 1,44,395

F. LJUNGSTRUNI. FASTENING THE BLADES OF Axial. STEAM TURBINES.

Fl LED JAN. 7. I920.

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' Application filed January v, 1920. serial No. aeaoii.

The present invention relates to an ar rangement in "axial steamturbines and has for its purpose to provlde for an attachment of the blades which is of a nature to permit of an easy replacement' of single bladefieretofore, the blades have been fastened by jamming them or otherwise attaching them in slots provided in the turbine rotor, the blades thus forming a rigid unit together with the rotor,'ywhich latter has not permitted of single blades or rings being removed for replacement by others.

blades are attached to blade-rings or disks, the latterbeing retained by a number of rings arranged beside each other and pressed together axlally in any convenient manner. These rings may also constitute parts of the turbinerotor itself. 7

The invention also consists therein that adjacent surfaces of the retaining rings and v the blade rings are machined so as to fit together when pressed against each other, the rings or the rotorparts being provided ontheir inner sides withprojecting ledges or thelike-of such a nature that the rings may be taken apart Without difficulty by hammer-blows or, by means of a tool set against the said ledges.

Further, the .invention consists. in the blade-rings being formed by ringsv in which the moving blades are inserted and welded in radially extendingslots.

The invention is illustrated infthe'accom panying drawing. Fig. 1 shows (partly diagrammatically) an axial-flow .turbine drawn'to a reduced scale, and Fig. 2 is a detail view'drawn to a larger scale. Figs. 3,

4L, 5. and 6 are sectional views of a bladev ring according to the invention during difb0.

ferent's'teps of manufacture. Figs. .7, 8,9

- in lan.

and 10 show the corresponding blade-rings The thread, oi course, has to be directed oppositely to the -direction of rotation of the turbine shaft.

a denotesthe steam passage (Fig. 2) with, the guide blades 5 and the moving blades 6 located therein. Thesection of the attachmerit 7 of thevmoving blades is formed so that it fits'between two adjacent rotor rings 8. Besides being shaped so as to con- ;veniently mesh with the blade-ring 7 by means or projectionsil3 and'lt, respectively,

the section of each rotor-ring 8 is alsoformed for engagement-with the adjacent.

rotor-rings by means oi. projections 15 and 1b respectively. n the inside, the rotor rings are provided with Ia'projecting ledge, boss or the like 9 so as to facilitate the taking apart of the ringsby means of a suit-i able tool set up against the said'ledge.

The Figures 3-10 show four different steps I in the manufacture of the blade-rings. The The invention consists therein that they original ring 7 is provided at the top with an lE-shaped ring 7* which is connected with the ring 7 by means of a narrow web 7. In the ring 7* there are provided slots 11 (Fig. 7) milled or otherwise worked into the material, the bases 1.7 of the blades 12 being fitted into said slots. Figs. 4 and 8 illustrate the present state of the blade ring.

By welding there is applied some material 7 around the blade bases, as will be seen from Figs. 5 and 9. I

By cutting on the line -AA- of Fig. 5 and turning in the lathe, the final form of the ring 7 is obtained as shown in Figs. 6

and 10. When assembling the rotor, the prov -jections 13 and 14: respectively of the rings 8 enter the interstices 18.

Upon cutting the web 7, thev ring 7 may be used to produce other blade rings.

VVhat ll claim as new and desire to secure by Letters Patent of the United States is 1. An axial flow turbine rotor composed of rotor rings clamped together so as to lie close to one another and forming'the turbine forming rings, projections onone set of said rings, and the other set of rings being formed with corresponding recesses meshing with said projections. v

3. An axial-flow turbine rotor as claimed in claim 1 wherein flanges. are provided on [and extending at substantial right angles from the sides of the first mentioned rotor rings and are positioned to face each other,

"form a rigid unit when connected together. 15'v 4e.-An axial-flow turbine rotor as-claimed in clairn 1 wherein the blade carrying'rings are provided with n circular ooves on opposite sides and corresponiiig flan es at substantially right angles from the a jacent sides of the rotor rings for engagement with the grooves so that the several rin s and blades form a rigid unit when assem led.

5;. An axial-flow turbine rotor as set forth in claim 1 wherein the rotor rmgs are pro;

vided on {the inside with abutting surfaces,

substantially as described.

In testimony whereot ll affix my signature in presence oftwo witnesses.

Withessesz 3G. BERGROBH, lEqHeon.

I FREDRIKLJUNGSTRQM. 

